Difference between revisions of "Jaw movements analysis. Part 1: Electrognathographic Replicator"

Jaw movements analysis. Part 1: Electrognathographic Replicator (view source)

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 This would not have been sufficient to complete the instrument and make it an actual 6-degree-of-freedom replicator because electrognathographic systems unequivocally and irremediably lose an angular degree of freedom on the <math>Y</math> axis visible on the sagittal plane (figure 5). In this case, in addition to the limit due to mixing, inversion, and summation of the Hall effect sensors (resolvable as mentioned), there would be a physical limit due to the lack of variation of the magnetic field in rotations on the <math>Y</math> axis. Practically, if a magnet is rotated between the fingers along its long axis, the magnetic field remains the same.
-Mandibular kinematics, in fact, is complex, and if we consider only the opening of the mandible, to facilitate explanation, it immediately becomes apparent that the condylar trace during mandible opening (from point 1 to 4) and, obviously, the analogous in closing (from point 4 to 1) generates an arc at the condylar level with a center positioned in the zygomatic region (Fig. 5). The steps from points 1-2, 2-3, and 3-4 generate arcs in which the entire stomatognathic system (condyle, condylar branch, and teeth, etc.) rotates clockwise by <math>14.8^\circ</math>, <math>10^\circ</math>, and <math>32.1^\circ</math> respectively. This parameter is fundamentally important from a rehabilitative gnathological point of view as it generates the free intra-occlusal space in the incisal area to allow harmonic and efficient excursion of the arches. This effect is mainly noticeable in the anterior quadrant as shown in Figure 6 where some occlusal parameters such as Centric in maximum intercuspation highlighted with contacts in red and the protrusive and lateral excursions in green are identified.
+Mandibular kinematics, in fact, is complex, and if we consider only protrusion to facilitate the explanation, it becomes immediately evident that the condylar trace during protrusion is similar to the opening of the mandible and generates an arc at the condylar level with a center positioned in the zygomatic region (Figure 5).
-<blockquote>
+The various protrusive steps generate a linear and angular displacement of the entire system with the formation of an angle (point 1-2 arbitrarily determined only to describe the concept) of 15.9°. The same phenomenon is reflected at the anterior level where the mandibular incisor moves linearly to the same extent, incorporating the counterclockwise rotation generated at the condylar level. This angular space is of fundamental importance because it constitutes the free interincisal space, an angular space necessary to allow the mandible to rotate and slide linearly during the execution of masticatory cutting activities. Indeed, the Sirognatograph and all electromagnetic gnathographic systems lose this angular data. This concept will be detailed in the specific chapters.<blockquote>
-It should be noted that the protrusive and lateral excursions should not be generated by calculating only the Angle of Condylar Eminence and Bennett Angle but integrating these first two parameters with the system's clockwise rotation, in the presented case of <math>14.8^\circ</math>, <math>10^\circ</math>, and <math>32.1^\circ</math>. These three integrated parameters generate the interincisal free space and the masticatory cutting effect.
+The various protrusive steps generate a linear and angular displacement of the entire system with the formation of an angle (point 1-2 arbitrarily determined only to describe the concept) of 15.9°. The same phenomenon is reflected at the anterior level where the mandibular incisor moves linearly to the same extent, incorporating the counterclockwise rotation generated at the condylar level. This angular space is of fundamental importance because it constitutes the free interincisal space, an angular space necessary to allow the mandible to rotate and slide linearly during the execution of masticatory cutting activities. Indeed, the Sirognatograph and all electromagnetic gnathographic systems lose this angular data. This concept will be detailed in the specific chapters.
 </blockquote>
 <gallery mode="slideshow">
 File:Antenna.jpg|'''Figure 3:''' Representation of the Sirognathograph antenna containing Hall effect sensors
 File:Sirognathograph frontal angle.jpg|'''Figure 4:''' Representation of the real mandibular kinematics composed of simultaneous rotation and translation. Effect of losing an angular degree of freedom on the <math>X</math> axis
-File:Sirignathograph rotazione asse Y.jpg|'''Figure 5:''' Representation of the real mandibular kinematics composed of simultaneous rotation and translation. Effect of losing an angular degree of freedom on the <math>Y</math> axis
+File:Rototraslazione Y.jpg|'''Figure 5:''' Representation of the real mandibular kinematics composed of simultaneous rotation and translation. Effect of losing an angular degree of freedom on the <math>Y</math> axis
 File:0041.jpg|'''Figure 6:''' Realization of the occlusal table in anterior disclusion contemplating the parameters of Condylar Eminence Angle, Bennett Angle integrated with the system's clockwise rotations.
 </gallery>
 {{q2|So then Lund & Co. were right to say that many clinicians who purchase jaw tracking devices are encouraged to use them to monitor their patients and that this is not justified because there is no evidence that the measured variables are highly correlated with the severity of TMD.|Certainly, but one cannot exclude instrumental diagnostic support in modern medicine because in this case, the non-correlation of clinical data is not due to errors and intellectual honesty of clinicians but due to inadequate engineering modeling of the instrument.}}